The present invention relates to a method for safely restraining occupants in a crashing vehicle, and a seat constructed to perform this method. More particularly, the invention relates to a technique to obtain a safe and gentle restraint of passengers/driver by using a safety belt that is integral with the seat.
The advantages of being restrained by a safety belt to avoid injuries in a crashing car are well known. However, there are problems as to how to attach the safety belts in a limited space, for example in buses and in other modes of public transportation.
The use of safety belts in public transportation involves problems regarding a safe attachment of the safety belts in the vehicle or to a seat. An attachment in the seat of the type used today must involve a rigid and voluminous construction which will occupy some of the useful space in the vehicle. An attachment outside the seat must have rigid points of attachment also occupying some of the useful space in the vehicle and requiring a great strength of the vehicle's walls and floor. Further, the attachment of the safety belts in the vehicle should not increase the risk of injuries to other passengers.
DE-A-2 546 157 discloses a back rest of a vehicle seat with a built-in safety belt, the back rest being resiliently collapsible while being in its transverse direction. This construction cannot absorb any greater loads and is seemed to be very dangerous at crashes over 30 km/h. Thus, at greater loads the resiliency being obtained comes suddenly to an end and the created shock is believed to be fatal for an occupant using the belt.
U.S. Pat. No. 4,993,778 discloses a seat construction with an integral safety belt. The attachment of the belt is secured outside the seat. This construction is not made to accumulate the loads in a crash.
WO 9014245 is one example of a seat construction being extremely solid. In a crash with this construction there is nothing making a gentle, progressive restraint of the occupant possible. This document is one example of a voluminous and heavy construction without refinements. The same can be said about EP-0 590 237 in which an effort has been made to get a slim construction. However the construction is very complex and probably rather heavy.